大奖!《石》在给大家信心

本刊今年第4期《从大镀金奖极限展品(石)说起》一文围绕拙集作了广泛的议论，现对文中所提到内地一些评审员所持观点与欧美评审员有出入的3个观点，略作回复，并再补充3点内容如下：

Lipopolysaccharide preconditioning induces protection against lipopolysac-charide -induced neurotoxicity in organotypic midbrain slice culture

Objective To identify the protective effect of lipopolysaccharide （LPS） preconditioning against LPS-induced inflammatory damage in dopaminergic neurons of midbrain slice culture and the possible mechanisms. Methods After cultured in vitro for 14 d, the rat organotypic midbrain slices were pretreated with different concentrations （0, 1, 3, 6 or 10 ng/mL） of LPS for 24 h followed by treatment with 100 ng/mL LPS for 72 h. The whole slice viability was detelmined by measurement of the activity of lactic acid dehydrogenase （LDH）. Tyrosine hydroxylase-immunoreactive （TH-IR） neurons and CD 1 1 b/c equivalent-immunoreactive （OX-42-IR） microglia in the slices were observed by immunohistochemical method, and tumor necrosis factor-α （TNF-α levels in the culture media were detected by enzymelinked immunosorbent assays （ELISA）. Results In the slices treated with 100 ng/mL LPS for 72 h, the number of TH-IR neurons reduced from 191± 12 in the control slices to 46±4, and the LDH activity elevated obviously （P 〈 0.01）, along with remarkably increased number of OX-42-IR cells and production of TNF-α （P 〈 0.01）. Preconditioning with 3 or 6 ng/mL LPS attenuated neuron loss （the number of TH-IR neurons increased to 126± 12 and 180± 13, respectively） and markedly reduced LDH levels （P 〈 0.05）, accompanied by significant decreases of OX-42-IR microglia activation and TNF-α production （P 〈 0.05）. Conclusion Low-dose LPS preconditioning could protect dopaminergic neurons against inflammatory damage in rat midbrain slice culture, and inhibition of microglial activation and reduction of the proinflammatory factor TNF-α production may contribute to this protective effect. Further understanding the underlying mechanism of LPS preconditioning may open a new window for treatment of Parkinson＇s disease.

From MEMS to NEMS： Smart Chips with Senses and Muscles

The last half-century was transformed by the electronic revolution that essentially reproduced the human brain and its computing capacity on a chip. But over time, scientists have realized that something was missing to give life, so to speak, to the small chip with a brain： One needed to awaken its senses and develop its muscles! This challenge was solved through MEMS （micro electro mechanical systems）. Indeed, MEMS today are equipped with the sense of sight, smell, hearing, taste and touch through microsensors. They are also capable of physical exertion through small muscles called microactuators. These new capabilities open wide fields of imagination and important specific applications.

Sensory and Organoleptic Characteristic, Zinc and Iron Content of Fortified Chips from Cassava Flour

Iron fortification can cause several biophysicochemical modifications. Those depend on many factors, such as iron fortificant and the food carrier. There were four groups of chips： 1） non-fortified wheat flour chips （K1）; 2） non-fortified cassava flour chips （K2）; 3） fortified cassava flour chips, each with ZnSO4 30 ppm and NaFe EDTA （K3） 30 ppm and 4） fortified cassava flour chips, each with ZnSO4 50 ppm and NaFe EDTA （K4） 50 ppm. The chips were evaluated for sensory characteristic （color, taste, flavor, and texture）, organoleptic characteristics tested by preference test, as well as zinc and iron contents. Zinc and iron contents were analyzed by Atomic Absorption Spectophotometric method. The results showed that both fortificants did not affect the sensory characteristic of cassava flour chips. The preference test showed that color, taste, and flavor of Kl chips as a control, were mostly liked, but there was no significant difference preference of texture. Moreover, preference test using K2 as control showed that color of K3 was mostly liked, but there was no significant difference preference of taste, flavor and texture. Fortification can increase the contents of zinc and iron in cassava flour chips. The panelist can accept the fortified cassava chips as well as wheat flour chip, as a consequence, both can be a potential way to combat the iron deficiency anemia.

Effects of Cultivar, Frying Temperature and Slice Thickness on Oil Uptake and Sensory Quality of Potato Crisps Processed from Four Kenyan Potato Cultivars

The effects of potato cultivar, frying temperature and slice thickness on oil uptake and sensory quality of potato crisps were investigated in four Kenyan cultivars. Potato tubers were peeled, washed and cut into slices of thickness 1.0 mm, 1.5 mm and 2.0 mm. Each size was fried at a constant temperature of 170 ℃ for 3-5 minutes. For frying temperature evaluation, the potatoes for all cultivars were cut into a uniform thickness of 1.5 mm and fried at temperatures of 160, 170 and 180 ℃ for 2-5 minutes. Crisps made from the four cultivars differed significantly （P 〈 0.05） in oil absorbed which ranged from 35.12% in Dutch Robyjn to 36.52% in clone 391,691.96. Tuber dry matter differed significantly （P 〈 0.05） among the cultivars ranging from 20.99% in clone 391691.96 to 25.29% in variety Dutch Robyjn. Tuber dry matter content was found to be negatively correlated to oil content of crisps; oil content increased with decrease in dry matter content. For each cultivar, the oil content of crisps differed significantly （P 〈 0.05） with temperatures and was higher at frying temperatures of 160 ℃ and lowest at 180 ℃, respectively. The oil content was significantly （P 〈 0.05） higher in slices of 1.0 mm thick than in slices of 1.5 mm and 2.0 mm; the amount ofoil absorbed decreased with increase in slice thickness. There was significant correlation （P 〈 0.05, r = -0.834） between oil content as determined in the laboratory and sensory scores. Results showed that high dry matter, slice thickness and temperature of frying resulted in reduced oil absorption by crisps during processing.

Chip-based visual detection of micro RNA using DNA-functionalized gold nanoparticles

In the present study, we developed a highly sensitive and convenient biosensor consisting of gold nanoparticle （AuNP） probes and a gene chip to detect microRNAs （miRNAs）. Specific oligonucleotides were attached to the glass surface as capture probes for the target miRNAs, which were then detected via hybridization to the AuNP probes. The signal was amplified via the re- duction of HAuCI4 by H202. The use of a single AuNP probe detected 10 pmol L-1 of target miRNA. The recovery rate for miR-126 from fetal bovine serum was 81.5%-109.1%. The biosensor detection of miR-126 in total RNA extracted from lung cancer tissues was consistent with the quantitative PCR （qPCR） results. The use of two AuNP probes further improved the de- tection sensitivity such that even 1 fmol L-t of target miR-125a-5p was detectable. This assay takes less than 1 h to complete and the results can be observed by the naked eye, The platform simultaneously detected lung cancer related miR-126 and miR-125a-5p. Therefore, this low cost, rapid, and convenient technology could be used for ultrasensitive and robust visual miRNA detection.

Organs on microfluidic chips:a mini review

Microfluidic technology provides opportunities to create in vitro models with physiological microenvironment for cell study.Introducing the identified key aspects,including tissue-tissue interfaces,spatiotemporal chemical gradients,and dynamic mechanical forces,of living organs into the microfluidic system,"organs-on-chips"display an unprecedented application potential in a lot of biological fields such as fundamental physiological and pathophysiological research,drug efficacy and toxicity testing,and clinical diagnosis.Here,we review the recent development of organs-on-chips and briefly discuss their future challenges.